Author: Nathan    Shunk

Major: Marine Sciences

Graduation Year: 2021

Thesis Advisor: Andrew Thomas

Description of Publication: Nitrate, temperature, and salinity conditions in the coastal upwelling regions of the California Current System vary on decadal timescales due to El Nino Southern Oscillation (ENSO) cycles. This study examines the quarterly variations in these conditions over the period 1979 to 2018 for CalCOFI cross-shelf transect 80, located at Point Conception. The CalCOFI dataset was indexed by NOAA’s Multivariate ENSO Index version two, climatologies were formed over El Nino, La Nina, and neutral quarters and then anomalies were calculated from these climatologies. Variations are most predominantly visible in the upper 200m of the water column and can be seen both coastally and offshore. Nitrate and temperature varied the greatest in the second quarter, during the period of greatest upwelling. La Nina (El Nino) periods saw greater (lower) concentrations of nitrate in the surface coastal water column. The nitrate-density relationships were similar between El Nino, La Nina and neutral periods and a difference could not be determined.

Location of Publication:

URL to Thesis: https://digitalcommons.library.umaine.edu/honors/700/